The ntoskrnl.exe is basically the system kernel, which is an integral component of Windows NT based operating systems. Kernel image is another name that it’s known by, but ultimately, its task is to provide both the executive layers and kernel of Windows NT. These are functions which are responsible for a number of different systems that make up the operating system (OS), such as the memory management, hardware virtualisation and processing.

This particular error is fairly common amongst all versions of Microsoft Windows, so hopefully the information contained in this post will help you resolve your particular problem. The 0xC0000005 Access Violation error is very broad as it encompasses a number of different problems. Due to this reality, you will be required to try an assortment of solutions to rectify your problem. Typically, when the error occurs, you will receive a familiar error message.

Winlogon.exe is a very important component of Microsoft’s operating system, as it handles the security and loading of the user profile, during the log in phase. It also handles desktop locking, when the screensaver has been activated, requiring the user to re-authenticate. Because of the importance of this component, it is a very common target by hackers.

The cli.exe file is a Command Line Interface for the ATi that works in the background and functions as a line of communication between the graphics card drivers and the ATi Catalyst Control Center application. While operational, an icon should be present in your system tray, which you can use to quickly access the Control Center application.